Collapsible tube closure and method of forming the same



c. J. was-rm 1,989,031

GQLLAPSIBLE TUBE CLOSURE AND METHOD OF FORMING THE SAME Jan. 22, 1935.

Filed Nov. 7, 1952 IrraP/I )4 W/IWESS: I flaw (Zars Patented Jan. 22, 1935 COLLAPSI BLE TUBE CLOSURE AND METHOD 0F FORMING THE SAIME Charles J. Westin, Philadelphia, Pa., assignor to F. J. Stokes Machine Company, Philadelphia, Pa., a corporation of Pennsylvania Application November 7, 1922, Serial No. 641,553

6 Claims.

In the beginning collapsible tubes were sealed, after filling, by making one or more folds in the end, in' a well understood manner. The pressure required to extrude some products through the orifice of the tube frequently burst the folded end. To overcome this, metal clips were attached over the fold and indentations were made through the applied clip for securing it in position. This involved considerable expense, and in order to eliminate the added cost of the clips various types of improved folds have been devised whereby the walls of the tube have, by folding, been made to act as their own clip. Such improved folds are usually re-enforced with corrugations. extending completely across the fold and through the edges or creases of the fold, and the bursting strength of the fold increases in proportion to the depth of the corrugations. However, in producing the crimps or corrugations, the same metal is stretched and bent in two directions, ,once when the creases in the folds are made, and once in making the corrugations and these stresses increase proportionately to their depth. It follows that the samemetal is under double stress and is fatigued or hardened and is thereby weakened to such an extent that cracks or pin holes are produced in the creases of the fold, which means a defective tube with ruined material. u

The principal object ofthe present invention is to obviate the above mentioned defects and disadvantages and to increase the strength of the fold and to avoid and eliminate leaks in the tube. According to the present invention this is done by reducing the length of the indentations or corrugations so that they do not extend to the edges of the folds, or, in other words, across the creases, and the increase in strength is by actual test, depending upon the kind of metal used, from 20 to 50%, as compared with the folds in which the corrugations extend to and through the edges of the fold, or, in other words, to or through the creases.

Tests have further demonstrated that the well known double fold tube closures, as shown in Fig. 4, when indented according to this invention have even greater resistance to leaks than when reinforced with a separate metal clip.

It is an advantage of the present invention that very heavy pressure can be applied in making the crimps or indentations, because the metal is not stretched or fatigued in two directions and the heavy pressure not only closely associates or interlocks the metal of the folds which more effectively seals the tube, but also may be used to provide deeper indentations or corrugations which add strength. In some cases deep pits are made at the center portions of the indentations and the lines of demarkation of the walls of the indentations surrounding the deep-pits may diverge towards the edges of the folds without however actually merging with the creases, so'

that the margins between the pits and the edges of the folds are substantially or practically straight. In looking at Fig. 2 it is clear that the margin is in effect a straight bar arranged centrally of the corrugations.

Generally stated, the invention comprises a collapsible tube closure comprising a folded end having a row or group of indentations spaced inwards from the creased edges of the fold and providing a margin of transversely unstressed metal.

The invention also comprises a novel process of closing collapsible tubes.

, The invention also comprises the improvements to be presently described and finally claimed.

In the following description reference will be made to the accompanying drawing forming part hereof and in which Figure 1 is an enlarged view of a collapsible tu'be closure embodying the invention in one of its forms.

Fig. 2 is an end view of the same.

Figs. 3 and 4 are views somewhat diagrammatically illustrating some, but not all, forms of folded tube end closures to which the invention is applicable, and

Fig. 5 is a side view of Fig. 1.

In the drawing 1 indicates a row or group of indentations or depressions 2, forming on the opposite surface beads 22. This row or group of indentations is spaced from the creased portion 3 at the end of the fold, providing margins 4 and 5 of unstressed metal, or metal unstressed by corrugating the fold, or metal free from stresses such, as would be produced by transversely crimping or corrugating the creases of the fold. It may also be noticed from an examination of Fig. 2 that the adjacent indentations on opposite sides are spaced longitudinally'of the folded end portion a suflicient distance apart so that the metal will not be unduly squeezed between the sides of opposing indentingpunches. The space betweenthe indentations is occupied by a bead 22 as seen in Fig. 2. I have found that excessive squeezing of the folds between the indenting punches will have the same detrimental. and weakening effect on'the tightness of the closure as previously described for the stressing of the creases in two or more directions. I, therefore, make the pitch, which is the term used for the distance between two adjacent, indenting punches and, therefore, also the space between the adjacent indentations on the same side, of such adimension that the portion of the folds forming the wall between the indentations is firmly pressed together but not pressed so tight as to distort or decrease the thickness of the folds at that point.

Herein the term folded end portion is applied to the' flattened walls of the tube which form the closure or seal. The term fold is applied to the portion of the flattened walls of the tube between the end of the tube and a crease, or between two creases of the folded end portion. The term "crease is applied to the line or edge of the flattened walls of the tube about which a bend is made. I

My invention also consists in a process of closing the end of a collapsible tube, which ,iprocess comprises, flattening the walls of the end of a tube, folding portions of said flattened walls about a crease to form a folded end portion, anddisplacing parts of the entire thickness of said folded end portion out of the plane of said folded end portion, thereby forming on each face of said folded end portion a corrugated row of alternate beads and indentations, the walls connecting the tops of said beadsv and the bottoms of said indentations being at an angle to the plane of said folded end portion, and flat margins of unstressed metal between said corrugated row and the end of said folded end portion and between said corrugated row and the crease in said folded end portion, said corrugations being suflicient to retain the tube tightly closed without the use of a separate metallic clip.

What I claim is:

1. A clipless collapsible tube closure adapted for frequent manual handling comprising a folded end portion of a tube having indentations therein, said indentations displacing parts of said folded end portion out of the plane of said folded end portion thereby forming on each face of said folded end portion a corrugated row of alternate beads and indentations, the walls connecting the tops of said beads and the bottoms of said indentations being at an angle to the plane of said folded end portion, and flat margins of unstressed metal between said corrugated row and the end ofsaid folded end portion and between said corrugated row and the crease in said folded end portion.

2. A process of closing the end of a collapsible tube without the use of a separate metallic clip,

said process comprising, flattening the walls of the end of said tube, folding portions of said flattened walls about creases to form a folded end portion, and impressing indentations in the flattened walls alternately on opposite sides of said folded end portion so that the portions of the walls between the alternate indentations form the walls of said indentations, said indentations being spaced from said creased edges of said folded end portion by an appreciable width of an unindented portion of said folded end portion.

3. A process of closing the end of a collapsible tube without the use of a separate metallic clip, said process comprising, flattening the walls of the end of the tube, folding a portion of said flattened walls about a crease to form a folded end portion, and displacing parts of the entire thickness of said folded end portion out of the plane of said folded end portion thereby forming on each face of said folded end portion a corrugated row of alternate beads and indentations, the walls connecting the tops of said beads and the bottoms of said indentations being at an angle to the plane of said folded end portion, and flat margins of unstressed metal between said corrugated row and the end of said folded end portion and between said corrugated row and the crease in said folded end portion.

4. A clipless collapsibletube closure comprising a folded end portion .of a tube having indentations forming a line of concavo-convex corrugations in the entire thickness of said folded end portion spaced from the creases of the folded end portion to provide margins of unstressed metal.

5. A clipless collapsible tube closurecomprising a folded end portion of a tube having indentations having substantially flat bottoms and polygonal shaped outlines pressed alternately in the center of the side of the folded end portion and aligned with the axis of the tube and diverging towards the creases of the folded end portion and spaced from the creases to provide fiat unbroken margins of unstressed metal the full length of the creases.

6. A clipless seal for a collapsible tube compris- 1 ing a folded end portion formed of folds made of the flattened walls of the tube, and indentations alternately impressed in the flattened walls on opposite sides of said folded end portion so that the portions of the walls between the alternate 

